This invention relates to a multi-layer shoe insole.
Many efforts have been made to provide shoe insoles having advantageous combinations of characteristics or properties such as insulation, strength, durability and comfort. For example, as disclosed in U.S. Pat. No. 4,263,727 to Bender et al., a sheet for the manufacture of cushioned insoles comprises a substrate of bonded fibrous material flame laminated to a foamed plastic layer composed of closed-cell crosslinked polyolefin, particularly polyethylene. A woven cover layer is likewise flame laminated to a side of the foam layer opposite the substrate. The insole material automatically adapts itself to the orthopedic shape of a foot in the various zones thereof and possesses high resistance to chemical aging.
As set forth in U.S. Pat. No. 4,055,699, a multi-layer shoe insole particularly adapted to insulate the foot from cold developed in the shoe sole owing to the wearer's walking on a cold surface comprises a thin top layer of nylon felt material, a second layer of thermoplastic foam cushioning material immediately beneath the top layer, a third layer of cross-linked high density polyethylene and a bottom layer of aluminum coated polymeric material. The second layer of the insole is preferably made of polyurethane foam impregnated with polyvinyl chloride foam. The bottom layer is embossed to provide a pebble-grain effect for preventing the insole from slipping within an article of footwear.
U.S. Pat. No. 2,736,109 is directed to a laminated insole including a central metallic layer disposed between two composite laminations each including an inner layer of foam latex and an outer layer of fabric material.
A shoe insole illustrated and described in U.S. Pat. No. 2,641,068 to Thompson includes an inner layer aluminum foil backed on one side by a sheet of gauze or other cloth and on an opposite side by a black heat-absorbing material such as black felt. On an outer side of the insole on the same side thereof as the heat-absorbing material is provided a layer of durable material such as light-weight woven cloth separate from or combined with the heat-absorbant material.
U.S. Pat. No. 2,284,947 to Clifford teaches a heat-insulating insole comprising a lower layer of aluminum foil and an upper layer of a relatively coarse fiber.
An object of the present invention is to provide an improved multi-layer shoe insole.
Another, more particular, object of the present invention is to provide an improved shoe insole which is especially effective in thermally insulating a wearer's foot.
Another particular object of the present invention is to provide such a shoe insole which additionally cushions the wearer's foot.
Yet another particular object of the present invention is to provide such a shoe insole which is flexible and yet strong.
A further object of the present invention is to provide such a shoe insole which absorbs and temporarily stores perspiration from the wearer's foot.
A yet further object of the present invention is to provide such a shoe insole which has a smooth peripheral edge.
Another particular object of the present invention is to provide such a shoe insole with a readily removable arch support member and a readily removable heal support member.